Improvement in processes and apparatus for leaching tan-bark



J. J. JoHNsToN. PROCESS AND APPARATUS FOR LEACHING'TAN-BARK.

No. 193.120. I Patented J'u1y17,18=77.

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////l/////////////////////////I////I////////////// MIHESSBE mEnIm PETais. PHOTO-LITMOGRAPHER, WASHINGTON. D. c.

w UNITED i IMPROVEMENT IN PROCESSES AND APPARATUS FOR LEACHING TAN-BARK.

specification forming part of Letters Patent No. 193,! 20, dated July 17, 1877 application filed June 9,

To all whom z't may concern:

Be it known that I, JAMES J. JoHNs'r0N, of Columbiana, in the County of Golumbiana and' State of Ohio, have invented a certain new and useful Improvement in Process and Apparatus for Leaching Bark for Tanning; and I 'do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

My invention relates to an improvement in process and apparatus for leaching bark for obtaining liquor for tanning purposes; and consists in placing suitable bark in a vessel, and partly exhausting the air from the vessel 'and bark, so as'to form a partial vacuum in the vessel and cells in the bark, and subsequently furnishing the bark in the vessel with a sufficient supply of water, which is caused to pass a number of times through the whole body of the bark, by turning the vessel on its aXis, and finally forcing the liquor from the bark by atmospheric pressure.

To enable others skilled in the art with which my invention is most nearly connected to make and use it, I will proceed to describe its construction and operation.

In the accompanying drawings, which form part of my specification, Figure 1 is an end view of a leach or vessel which I use for leaching bark for obtaining a liquor for tanning purposes. Fig. 2 is a transverse section of said leach or Vessel. Fig. 3 is a vertical and longitudinal section of said leach or vessel.

In .the accompanying drawings, A represents the body of the leach, which is constructed of oak plank of about three inches in thickness, formed into staves of any desired width. I have found that staves six inches wide answer best; but I wish it clearly understood that I do not confine myself to any one Width or thickness, nor kind of timber or other material, for the Construction of my inprovement in leach, but leave such matters to the judgment and skill of the mechanic.

The ends B are' provided with cross-pieces C for strengthening them. To the pieces G are secured trunnions D, by means of bolts e, the heads of which must be covered with brass or copper, (cast over the heads,) to premeans of a strong gum hose or by a brass or I Copper pipe, with an air-engine.

The joints in the leach A should be calked, and the hoops or bands used for holding the staves (as in a barrel) must be made strong.

The leach is mounted on a frame, which' should be sufficiently high to allow the workman to stand under it for the purpose of removin g the waste bark. The trunnions D should be placed in suitable bearings in the supporting-frame of the leach A.

The outer walls of the leach should be coated with paint.

The operation of my improvement is as follows: The bark is ground in the usual manner and by the ordinary means, and conveyed to the leach by elevators, the Construction of which is well understood. The compartment j is filled with the ground bark and the doorf closed. The air-engine being connected to the valve lof the compartment Ic the air is partly exhausted from the leach and cells of the bark.

The valve l of the *compartment i being connected with a water-supply, the compartment ?I is filled with water, which passes through the partition g, and is thereby evenly distrib-- uted to the bark in the chamberj, from which the liquor flows through the perforations in the partition g into the compartment k. The leach A is then turned on its axis, so as to bring the compartment k uppermost, and the liquor in it fiows again through the bark and into the compartment i. Thus is the leach turned alternately, changing the position of the compartments i and k, causing the liquor to flow several times through the bark in the compartmentj.

While the liquor is flowing from the compartment which is uppermost down through the bark into the lower compartment, the airengine should be exhausting the air from the,

upper'coinpartnent, s'o Operating ;the engine as to remove oniy'part of the 'air from the several compartments and cells of the bark.

I have found that removing one-half theair answers a good purpose, and will not subject the leach A to too much 'external atispherici pressure, which must be guarded against;

otherwise the leach A will be injured by un-.

due pressure.

After the liquor has flowed a number of times through the bark it is drawn ofl' into a suitable rec'ei`vin g vessel. During the time* the liquor is flo'wing from the lower compartment of the leach, air should be forced into.

so as to bring the door f on the under side of the leach. It is theu opened and the bark' discharged from the 'leach into a suitable de vice for carrying it of to a suitable -place'of deposit. The leach is *then turned 'seas to bring the door f uppermost, and the'compar't ment 7' is 'again filled lwith bark, which is's'ubjected to the leaching'proce'ss, as hereinb'efore described.

By means of the ieach A, constructedand operated as described, bark 'can be i'apid'ly,

i'ach'ed, and much time and labr saved, and

the tanning-liquor increased in strength to "anydesired degree. y

These facts have been fully demonstrated "by 'a ;practise-1 tes t of' a large leach constructed as set forth.

Having thus described myvimprovemeut in process and 'a'paratis forbbtihing liquor for tanning purposes, what I claim as of my invention is i 1. The -pr'ess'- h reinbfre described for le'aching bark for obtaining liquor for tanniug .purposes-viz., placing bark in a vessel, and pa'rtly exhausting the air from said vessel and the cells of the bark, and up'pyi i't "with watr,`which is missed to flow 'through it a number of "times, fahd* 'subsquentl f'rci'h'g the liqiorfrom said'vesse and bark 'by atmospjheric meshire; V f

2. The 'ves'se *or ach ec, pvotedbn ?truni-iosfand divide'd ito'conpartm'euts i, j, 'and k by pertoratd prtitioi's 'g, the com'pa`rt*- nichts n'd k havii g each a vlve, l, and the compar'tme'n't 37' a door, f, substantia'llyas er-e in described, and for the purpose set f'rth.

JAMES "Ji JOHNSTN;

A. 0. JOHNSTON, WESLEY'JOHNSTN; 

